According to the present invention there is provided a mechanical thruster for positively separating two joined components from each other under a controlled time delay. More particularly there is provided a time controlled device for mechanically opening survival kit containers carried in aircraft as the containers are being dropped to a target area.
Military and civilian long range search and rescue operations often require the dropping of survival kits containing food, medical supplies, radio equipment and, at sea, life rafts, from an airplane to a target area in the vicinity of a person to be rescued. In the past, survival kits have been carried in the cockpits of the search and rescue planes and manually dropped, through an open window in the plane, to the target area. A more accurate method of dropping such survival kits to persons awaiting rescue has been to carry the kits in canisters or containers having a separable lid, such containers being carried on the wings or in the bomb bays of the airplane. Such containers are secured to the plane by securing means mechanically or electronically releasable by the pilot or a crew member of the airplane. At the time of release, a pyrotechnic thruster unit, secured to the container is actuated by extraction of an arming cable or pin therefrom. After a predetermined time a charge in the thruster explodes causing the parts of the thruster to separate with the container lid and enabling the container contents to be discharged. If the survival kit is attached to a parachute, the parachute then opens, and the survival kit commences a slow descent to the rescue site.
Such pyrotechnic thruster devices, because of their very nature, possess inherent problems and disadvantages. Because they contain explosive charges, they are inherently dangerous. They must be inspected and controlled over a period of time because of the gradual deterioration of the explosive materials used. Such devices do not permit variation at the time for actuation, thus prohibiting a pilot from adjusting the delivery trajectory of the survival kit to the rescue area according to plane altitude, wind and weather conditions and the like. As well, there is always the possibility of electromagnetic interference from the aircraft which might prematurely cause such a pyrotechnic thruster to become actuated and its charge to explode.
It is an object of the present invention, therefore, to provide a thruster unit for opening containers, for example, for survival kits, by purely mechanical means. It is a further object of the present invention to provide an adjustable time delay in the actuation of such a thruster unit.